From the Guidelines
Myopathy and optic neuropathy in the context of thyroid eye disease (TED) require prompt and comprehensive management to prevent vision loss and improve quality of life, as emphasized in the most recent guidelines 1. The connection between myopathy and optic neuropathy in TED is rooted in the autoimmune nature of the disease, which can lead to congestion and inflammation of the orbit and surrounding tissues, resulting in restrictive extraocular myopathy and optic neuropathy 1. Key aspects of management include:
- Counseling the patient on the diagnosis and treatment options
- Carefully monitoring patients at risk for vision loss secondary to compressive optic neuropathy
- Managing binocular diplopia, compensatory head posture, and associated elevation in intraocular pressure (IOP)
- Referring to an orbital specialist if the patient experiences vision-threatening disease, moderate-to-severe exophthalmos, and/or significant orbital pain related to TED 1. The most critical step in managing myopathy and optic neuropathy in TED is early diagnosis and referral to a specialist, as highlighted in the 2024 guidelines 1, to prevent long-term vision impairment and improve patient outcomes. Diagnostic tools such as optical coherence tomography, automated threshold visual fields, and orbital CT or MR imaging can confirm the diagnosis and evaluate the extent of muscle involvement and orbital fat volume 1. Thyroid function and associated immune studies should also be ordered, although this is typically handled by the associated primary care or endocrinology specialist 1. In summary, a comprehensive approach to managing myopathy and optic neuropathy in TED, as outlined in the most recent guidelines 1, is crucial to preventing vision loss and improving quality of life, and should include early diagnosis, specialist referral, and careful monitoring of patients at risk for vision loss.
From the Research
Myopathy and Optic Neuropathy
- Myopathy refers to a group of muscle diseases that are not caused by nerve disorders, whereas optic neuropathy refers to damage to the optic nerve, which can cause vision loss.
- There is limited direct evidence linking myopathy and optic neuropathy, however, some studies suggest that certain conditions can cause both muscle and optic nerve damage.
- For example, hereditary motor sensory neuropathy type VI (HMSN VI) is a condition that affects both the muscles and the optic nerves, causing optic neuropathy and muscle weakness 2.
- Coenzyme Q10 (CoQ10) has been proposed as a potential treatment for certain types of optic neuropathy, including those associated with mitochondrial myopathies 2, 3.
- In terms of diagnostic assessment, a clinical approach to optic neuropathies involves taking a thorough history, performing a physical examination, and using ancillary investigations such as visual field testing and neuro-imaging 4.
- Ocular myositis, a rare inflammatory disorder of the extraocular muscles, can cause painful diplopia and may be associated with other systemic diseases, including autoimmune disorders 5.
Optic Neuropathy Causes and Treatments
- Optic neuropathy can be caused by a variety of factors, including demyelinating diseases, inflammatory disorders, ischemia, and trauma 6, 4.
- Treatment for optic neuropathy depends on the underlying cause, and may include corticosteroids, immunosuppressive therapy, and plasma exchange 6.
- In some cases, CoQ10 may be used as a neuroprotective agent to slow or reverse pathological changes associated with optic neuropathy 2, 3.
Myopathy and Optic Neuropathy Relationship
- While there is limited direct evidence linking myopathy and optic neuropathy, certain conditions such as HMSN VI can cause both muscle and optic nerve damage.
- Further research is needed to fully understand the relationship between myopathy and optic neuropathy, and to develop effective treatments for these conditions.